In the United States,
more than half of the population reported owning a pet in 2011. This number has been quite steady since then. Today there are more than 90 million
cats in the United States, while the number of
dogs is just below the 90 million-mark. Freshwater fish are the
most common pet with almost 140 million nationwide in 2018, followed by the aforementioned cats and dogs.
 
Pet expenses
 
 When it comes to expenses, fish are generally considered low maintenance compared to other pets. Dogs especially
require high expense, particularly for kennel boarding while their owners are away. However, the highest costs for dog owners are due to surgical vet visits, reported at almost double the expense for cats in 2019. Lower life expectancy could be a factor - around 11 years for a medium-sized dog, compared with 12 to 15 years for cats.  
 
Pet food
 
Food is currently the largest expense for cat owners, and the second highest for dogs, not even including treats. Despite the convenience of buying pet food online, or while already grocery shopping in a supermarket, food store, or wholesale club, the highest
share of pet food sales comes from pet specialty chains. With many owners are willing to make the extra trip for their pets, chain shops Pet Smart and PetCo make up almost half the
market for pet companies in the United States.